package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;
    @Override
    public Result queryBlogById(Long id) {
        //查询blog
        Blog blog = getById(id);
        if (blog == null) {
            return Result.fail("笔记不存在！");
        }
        queryUserByBlog(blog);
        isLiked(blog);

        return Result.ok(blog);
    }

    private void queryUserByBlog(Blog blog) {
        //查询blog有关的用户
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    private void isLiked(Blog blog) {
        if (UserHolder.getUser() == null) {
            //用户未登录，无法查询
            return;
        }
        //查询用户是否被点赞
        Double score = stringRedisTemplate.opsForZSet().score(
                "blog:liked:" + blog.getId(),
                UserHolder.getUser().getId().toString()
        );

        blog.setIsLike(score != null);
    }

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            queryUserByBlog(blog);
            isLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result likeBlog(Long id) {
        //获取登录对象
        Long userId = UserHolder.getUser().getId();
        //判断是否已经点赞
        String key = "blog:liked:" + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //如果未点赞，可以点赞，数据库点赞数+1，保存用户到redis的set集合
        if (score==null){
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if (isSuccess){
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }
        //如果已点赞，取消点赞，数据库点赞数-1，从redis的set集合中移除用户
        else {
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            if (isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        //查询top5的点赞用户 zrange key 0 4
        String key = BLOG_LIKED_KEY + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        // 解析出其中的用户id
        List<Long> userIds = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", userIds);
        // 根据用户id查询用户
        List<User> users = userService.query().in("id", userIds).last("ORDER BY FIELD(id," +idStr+ ")")
                .list();
        List<UserDTO> userDTOList = users.stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        // 返回用户
        return Result.ok(userDTOList);
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isSucceed = save(blog);
        if(!isSucceed){
            return Result.fail("新增笔记失败!");
        }
        //查询笔记作者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        // 推送消息
        for (Follow follow : follows) {
            // 4.1.获取粉丝id
            Long userId = follow.getUserId();
            // 4.2.推送
           String key = FEED_KEY + userId;
           stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        return Result.ok(blog.getId());
        // 返回id
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //获取当前用户
        Long userId = UserHolder.getUser().getId();

        //查询收件箱
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key,0,max, offset, 2);
        if (typedTuples == null || typedTuples.isEmpty()) {
            return Result.ok();
        }
        //解析数据：blogId、minTime（时间戳）、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());

        long minTime = 0;
        int os = 1;
        for(ZSetOperations.TypedTuple<String> tuple : typedTuples)
            {
                String blogId = tuple.getValue();
                ids.add(Long.valueOf(blogId));
                long time = tuple.getScore().longValue();
                if (time == minTime){
                    os++;
                }else{
                    minTime = time;
                    os = 1;
                }
            }

        //根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Blog blog : blogs) {
            // 5.1.查询blog有关的用户
            queryUserByBlog(blog);
            // 5.2.查询blog是否被点赞
            isLiked(blog);
        }
        //封装结果
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);


        //返回
        return Result.ok(r);
    }
}
//@Override
//public Result likeBlog(Long id) {
//    //获取登录对象
//    Long userId = UserHolder.getUser().getId();
//    //判断是否已经点赞
//    String key = "blog:liked:" + id;
//    Boolean isMember = stringRedisTemplate.opsForSet().isMember(key, userId.toString());
//    //如果未点赞，可以点赞，数据库点赞数+1，保存用户到redis的set集合
//    if (Boolean.FALSE.equals(isMember)){
//        boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
//        if (isSuccess){
//            stringRedisTemplate.opsForSet().add(key,userId.toString());
//        }
//    }
//    //如果已点赞，取消点赞，数据库点赞数-1，从redis的set集合中移除用户
//    else {
//        boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
//        if (isSuccess){
//            stringRedisTemplate.opsForSet().remove(key,userId.toString());
//        }
//    }
//    return Result.ok();
//}